This invention relates to an image reading apparatus which reads the information of an original document by a photoelectric conversion element.
As the apparatus for reading image information of an original, for example, it has been developed an image reading apparatus as a film scanner which reads image information memorized in a developed photographic film by a photoelectric conversion element such as a CCD through an optical system. In such an apparatus as this, the read image is converted into digital data, which enables digital image processing, hence it is expected to come into wide use in the future.
The image reading apparatus which reads an image from an original such as a developed photographic film is composed of an original setting portion wherein the original is set, an imaging optical system which reads optically the image information recorded in the original, and a photoelectric conversion element portion which converts the image information from the imaging optical system into electrical signals.
Regarding such an apparatus as this, it has been known an image reading apparatus capable of using two kinds of film (J135 and IX240) having different formats. In general, in these image reading apparatus, because the film setting position, the lens position, and the position of the photoelectric conversion element are fixed, the size of the image focused on the photoelectric conversion element becomes smaller as the size of the film format (the size of the original) becomes smaller, hence the quantity of image information is reduced because of the constant image resolution (dpi).
This invention has been made in view of the problem mentioned above, and it is an object of the invention to provide an image reading apparatus capable of reading an image with a maximum resolution at any time with the image resolution made variable in accordance with the size of the original.
Hereinafter, preferable structures to attain the above object will be described.
(1) This invention solving the above-mentioned problem is an image reading apparatus wherein the image information of an original is focused on a photoelectric conversion element through an optical system, and the image information is read by said image conversion element, said apparatus further comprising image size detecting-or-specifying means for detecting or specifying the image size to be read, and varying means of resolution of the image to be read for varying the maximum resolution of the image to be read in accordance with the output of said image size detecting-or-specifying means.
According to the structure of the paragraph (1), by detecting the format size of the original set on the original setting portion by means of the image size detecting-or-specifying means or by specifying the format size of the original by the operator using the image size detecting-or-specifying means, the format size of the original is determined, and the varying means of the resolution of the image to be read makes it possible to read the image information with a maximum resolution at any time in accordance with the determined format size of the original.
(2) The aforesaid varying means of resolution of the image to be read is a lens for re-sizing.
According to the structure of the paragraph (2), the image can be read always with a maximum resolution by driving the lens for re-sizing in accordance with the format size of the original.
(3) The aforesaid varying means of resolution of the image to be read is a single focus lens and a photoelectric conversion element which are made up in such a manner as to move for re-sizing with a predetermined relationship maintained.
According to the structure of the paragraph (3), the image can be read always with a maximum resolution in accordance with the format size of the original, because the single focus lens and the photoelectric conversion element move for re-sizing with a predetermined relationship maintained.
(4) The aforesaid varying means of resolution of the image to be read is a single focus lens and an original setting portion which are made up in such a manner as to move for re-sizing with a predetermined relationship maintained.
According to the structure of the paragraph (4), the image can be read always with a maximum resolution in accordance with the format size of the original, because the single focus lens and the original setting portion move for re-sizing with a predetermined relationship maintained.
(5) The aforesaid varying means of resolution of the image to be read is an original setting portion and a photoelectric conversion element which are made up in such a manner as to move for re-sizing with a predetermined relationship maintained.
According to the structure of the paragraph (5), the image can be read always with a maximum resolution in accordance with the format size of the original, because the original setting portion and the photoelectric conversion element move for re-sizing with a predetermined relationship maintained.
(6) The aforesaid varying means of resolution of the image to be read is made up in such a manner that there is provided an original setting portion capable of being selected stepwise and a photoelectric conversion element moves for re-sizing to make a predetermined magnification in accordance with the selected original setting portion.
According to the structure of the paragraph (6), the image can be read with a maximum resolution at any time in accordance with the format size of the original, because the single focus lens is moved for re-sizing to make a predetermined magnification in accordance with the selected original setting portion.
(7) The aforesaid varying means of the resolution of the read image is provided with an original setting portion capable of being selected stepwise, and has a structure such that the photoelectric conversion element is moved for re-sizing to make a predetermined magnification in accordance with the selected original setting portion.
According to the structure of the paragraph (7), the image can be read with a maximum resolution at any time in accordance with the format size of the original, because the photoelectric conversion element is moved for re-sizing to make a predetermined magnification in accordance with the selected original setting portion.
(8) The aforesaid image size detecting-or-specifying means detects the image size by detecting the image width in the main scanning direction focused on the photoelectric conversion element.
According to the structure of the paragraph (8), the format size of the original can be detected because the width of the image focused on the photoelectric conversion varies in accordance with the size of the original.
(9) The aforesaid image size detecting-or-specifying means specifies the area for trimming on the image surface for the image indicated on a display means.
According to the structure of the paragraph (9), a specified area of the image indicated on the display means can be denoted as the area for trimming, and the specified area for trimming can be read with a maximum resolution.
(10) The magnification for trimming is calculated according to the ratio of the length of a half of the whole image length indicated on the display means in the main scanning direction to the distance from the edge farther from the central line with regard to the main scanning direction to said central line.
According to the structure of the paragraph (10), the area for trimming can be read with a maximum resolution by calculating the magnification for trimming according to the ratio of the half length of the image in the main scanning direction to the distance from the edge farther from the central line with regard to the main scanning direction to said central line.
(11) When the aforesaid image size detecting-or-specifying means specifies the area for trimming on the display means, the maximum image resolution or the quantity of the image data is indicated on the display means in accordance with the area for trimming.
According to the structure of the paragraph (11), when the area for trimming is specified, the maximum resolution of the specified area for trimming can be calculated And indicated on the display means so that it may be easy to understand for the operator. To state it concretely, it is indicated in such a manner as xe2x80x9c1200 dpixe2x80x9d.
(12) When the scanning of the image wherein the area for trimming is specified on the display means is to be carried out, the start position in the sub-scanning direction and the end position in the sub-scanning direction are moved in accordance with the area for trimming.
According to the structure of the paragraph (12), in the case where the area for trimming is specified, because it is not necessary for the whole area of a frame to be subjected to proper scanning, the area for proper scanning is made to be from the start position in the sub-scanning direction to the end position in the sub-scanning direction, hence the proper scanning can be carried out efficiently.
(13) When the image in which the area for trimming is specified on the display means is indicated again on the display means after it is subjected to the scanning, the scanned and read image is indicated only to the extent subjected to trimming.
According to the structure of the paragraph (13), only the area for trimming can be indicated with a maximum resolution on the display means.
(14) The aforesaid image size detecting-or-specifying means indicates the magnification for enlargement or the size of the original on the display means.
According to the structure of the paragraph (14), the image can be read with the magnification for enlargement or the size of original that is just specified by the operator.
(15) The aforesaid image size detecting-or-specifying means detects the image size to be read by the original size detecting means provided in the original setting portion.
According to the structure of the paragraph (15), the image size to be read can be detected by providing the means for detecting the size of the original in the original setting portion.